If someone is buying a product from you, it’s likely they could want another item that compliments the one already in their cart. Although, if a customer leaves your site after purchasing a single item, it’s still possible to upsell or increase the overall customer transactions.
The Upsell template is intended for publishers to automatically send emails offering related products (for instance, offer a course for customers of your new book). Simply setup the integration with Stripe and edit the emails to reflect your offer.